1. Field of the Invention
The field of the invention is dilatation catheters having evertable-invertible balloons for dilating strictures or stenoses of tubular elements and passageways of the body. More specifically, the field of the invention is the provision in such catheters of a central through lumen provided with means enabling the passage through the balloon of a guide wire or other element while providing a sealed balloon system at all times.
2. Description of the Prior Art
In the dilatation catheter art, it is old to provide such catheters with evertable-invertible balloon elements. Attention is directed to U.S. Pat. No. 4,254,774 in this regard. Such balloon catheters, however, have not, insofar as we are aware, been provided with sealed through lumens enabling the passage through the balloons of guide wires and other instruments.